Symptoms and their usual causes
| Usual suspects | Repair or replace? | |
|---|---|---|
| No hot water, electric tank | The element, the thermostat, or a tripped circuit | Usually a repair |
| No hot water, gas tank | The pilot, the gas control or the gas supply | Usually a repair |
| Instant gas unit won't fire | An igniter, a flow sensor or the gas supply; the controller often shows an error code | Usually a repair |
| Hot water runs out early | A failed element, or a system too small for the house | A repair, unless it's undersized |
| Drips from the relief valve drain | A worn valve, or pressure building as the water heats | Usually a repair |
| Water from the tank body | The inner tank has failed | Replace |
| Rust-coloured hot water | A spent anode or a corroding tank | Depends on the tank |
Checks before you book
You can
- Look at the switchboard: is the hot water circuit or a safety switch off?
- On an off-peak tariff, remember the tank may only heat at set hours.
- For gas, check the meter is on and the stove lights.
- Write down any error code shown on the controller.
- Find where any water is coming from, and take a photo.
Leave to a licensed plumber
- Opening the unit, and anything to do with elements, thermostats or wiring.
- Gas controls, burners, pilots and igniters.
- Relief valves, anodes and the other valves on the tank.
- Any smell of gas.
How a plumber will track it down
Start with the history
A plumber will ask about the age, the symptoms and what you've already checked, then read the model off the label.
Test, don't guess
On an electric unit they test the element and thermostat. On gas, they check the supply, the pilot or igniter, and the burner.
Look at the tank
Seepage, rust and the state of the valves tell them whether the tank is sound, which is what makes a repair worthwhile.
Give you the choice
You should hear what failed, what fixing it involves, and whether the tank is near its end anyway.
Repairing gas hot water in Victoria
Victoria's 2027 rule doesn't stop repairs. In the Government's words, "Gas hot water systems can still be repaired if they break down."
The rule bites at end of life: from 1 March 2027, an existing home whose gas system is finished must switch to an efficient electric one. Check current rules, and see the rule explained.
Licences and paperwork for a repair
NSW. Plumbing and gasfitting are specialist work. Anyone contracting to do them needs a contractor licence, whatever the job costs.
Western Australia. Repairing a water heater is minor work: it needs a record, but no certificate of compliance. Installing or replacing one is not minor work.
Victoria. A plumber is registered or licensed for each class of work. Ask which they hold for hot water and for gas.
Queensland. Queensland Health says any adjustment to the thermostat settings should be done by a licensed electrician.
Our licence check guide shows how to look a plumber up.
Red flags on a repair call
- You're told the tank is finished, but nobody shows you the leak.
- Pressure to sign for a new system on the spot.
- Advice to set the storage temperature below 60°C to save power. Water kept at 60°C or more is what holds Legionella growth down.
- No licence number when you ask for it.
- Someone at the door offering a VEU-discounted heat pump: doorknocking is banned under Victoria's VEU program.
What we would do
If the tank is dry and the fault is a part, repair it. If water is coming from the tank body, put the repair money towards the next system instead. Either way, use a plumber who specialises in hot water: they carry the common parts, they've seen your fault before, and they'll tell you straight which of the two you have.